Brake for use on hoisting devices.



H. GRAUMULLER.

BRAKE FOR USE ON HOISTING DEVICES.

APPLICATION FILED MAR. 27. I914. I

PatentedSept. 21, 1915.

2 SHEETS-SHEET I.

H. GRAUM'U'LLER.

BRAKE FOR USE ON HOISTING DEVICES.

A P P L l C A T l 0 N F l L E D M A R 2 7 I l 9 l 4.

1,154,501. Patentedsept. 21, 1915.

2 EEEEEEEEEEEE 2.

HERMANnLGnAUMfiLLER, OEBERIQILEQGERMANY."

BRAKE FoR' UsE "on Hamil-we. Devices-'5 s s-easement: Letfisl ream; meenta sepefzi, 1915.

Application men March 27, 19 14? Seria1 N6i -827709w To aZZMho-mvitimag concern):

Be =it- =known that :I,!=HERMANN"\ GR'AU'f: MfiLLEIQ' engineer, a citizen of ethe-sGermanl Empire, and resident :of) .CBerlin, Germany, have A inventedr certainnew and useful liner provernents in aBra-kess fora Use'zonaHois'tin'gr Devices; and I ;do;, hereby '-declare"the fol-+1 lowing to be: a :full; clear; and exact; deserlpe tion' ofwtherinyentiongi such-as, lWill .enable others skilled in theartto S'WhlChxlbJELPPQL'I-H tains; to make I and use: :the I same, reference being shad i130. T the; accompanying I dr21;WlIIg:S,'-'

and to letters or figures of reference marked thereon, which: s form I a :part' of ithis' specification:

This! invention relateseto akbrakeikforz use on such hoisting devices u-in which only :one brake; drum .-:is: :provided whichis rotatable in the hoisting :clirectiomv and ironez pairiiof brake *blocks or cheeks: which arevadaipted: to be operated-by a canr on -thetdrnm'eslia'i'ti,-

The: main [feature oftlie invention consists in 7 that the; earn :011 the drum-shaft is formed' by two essentially parallel opposite sur-facesi whose points; of contactri with: the; curved pressure transmitting; surfaces: of: the brak-"-' in g. echeeks' are positioned; opposite SOne' "fl1"1'-i: other in such a manner that"on'itheapplicw-s tion. of pressure on the two cheeks :a rolling-: 0E actiontakesplace atrthesurfaces incone tact, and .tha-t even in case: :any iamount bf play should happento oecur theleverage:of the turning. moment: which is exercised up on; the drum shaft by reacting aforcesv remains constant. in order :to; obtain brahingfiefli ciency which remains constantly'propor tional to'the'. hoisting:efliciencyw v The improvedibrakevi's suitable for heavy loads. Alterations in the' parts ofth'e brake which are i caused by Wear, (10 notvaffectethee operation-of the'brake'; as; there theleveragesdo i not alter; and conseqnentlywthe. sreaoting forces will reinainvjproportional under; the: same 'loadsa A jammingiioriwedgingmction of thewarions'zparts :is; rendered 5i1npossible.

In the aeoompanyingzdrawing. tv'vijorex-" amples of the invention are 'illnstratedza Figured is-a sectionthroughaone' construe;v tion, and=Fig-.:;2 is section onrline Ai-BJOIE Figx l'. FigeB shows a@IIlOdifiGdwfOflIli'Of;

' theoinnention; ofewhioh aFigialis :a *section onilineqGi:D ofeFig. I

In .'-these%-:drawingst.=il shaft while 2.:iis ith'eiiadrivingwmember by means of-Which theuload is hoisted- Iinskn'own manner-aaor-loweredtawhen; running :in'fireverseddireetion; lfOT' example :by means-of a control chain. 1 Thewdriunr shafit is provided with -:a cam. consisting-inf; two oppositely arrangedplpreferablyjs'parallel, straightasurfacesa3 anda l, whichi. are formed by 1 flattening she periphery :of/ the sh'afit near one? end thereof, ,(these 'snrfa cesrmay be: of a certaincnrlvatnree-ififdesi-red) rthe drivingipartfi :is monnteds'auponraneextension 5 1 of sh 'aftirlr Two :brake blocks or cheeks 6 and 7 are provided lwhich may r'be" hollows as -:usual and which-2: inayh aaie parts ou-t llII5OId6I1"l5O take upther gneaseor lubricant They :are adapt 6611130); bear; sagaiinst-a'thea inner side of the rim of thefbrake; dnnmS which latter is provided withizexternal teeth? adapted to be engaged by'a pawl 9. Theiinnernrostisurfaees 10fand- 11Qofitheebrake;eheeksrextend as ne'anas possiblerto thesshaft 15 and i'their: points oi contact 1: with. the: F parallel surfaces; 4: of the: shaft:- are diametrically opposites A projeoting part 'fiiservingas a cam is=provided onatheidrixdhg member Qrandis placed be-' tween 'thertwo eheeks 6 *anolgfil V 7 The device: works as; :follows When the driving member 2 is rotated towardwthe rightasein-dicated;by the arrow in :Fig. '1, it presses against the surface 18 *of the cheek 7 and: the "drunr; shaft presses with its-stir facen3 fag'ainst-wthe-asuriacer -11 of the-:same cheek 7,3while onithe: opposite side the sur faces l; presses :nagai nst'ithe surface 10v of the cheeks, 6; i Thus the :oheeks vand the :brake (1111111138, are'ieonpled together and the load is liftdh': r If: pn'llr :is exerted; onvthe driving membera :2 inwthe reverse direction, the" pro. r

jectinglpartuw will-ltend ltowwithdraw from contactowith'rthe cheek :7, thereby causing a reduction of. pressure- :in i the-braking icheeks and ltllGPlOildf' will: sink downwardly accordingito;therotation ofwpart 2.- Theinner surfaces-of the braking cheeks i 6 and 7 against Whl'fillk the: faces "3 and of thesdrum shaft arersadaptedi to 'bean-an'dvthe end faces -13" denotes: the dru'm By making the faces ofll, and 10, as well as of 18 and la rounded, as shown in the drawing, the further advantage is obtained that a'rolling'oif motion takes place between the surfaces in contact, instead of the usual sliding orgrinding motion, which prevents the formation of undesirable play, even i when the brake is frequently used. A small amount of wear between the surfaces 3,11, and 4, 10 will not cause jamming or clamping of the parts and even if play should occur, no alteration will take place in the leverage of the turning moment which is exerted by the reacting forces upon the drum shaft. Consequently the braking action will always be proportional to the lifting action. An advantage of this construction'consists also in that movable intermediate members, which would haveto transmit the force to thebraking cheeks, are entirely avoided.

In Figs. 3 and 4: like references are used for the corresponding parts. The diflerence in the construction as shown in these figures from that shown in Figs. 1' and 2 consists in that a bolt 15 is screwed to the driving member 2. This bolt lies obliquely between the surfaces 17, 18 of the braking shoes 6 and 7 respectively. It will be seen from Fig. 3 that when pressing the bolt 15 downwardly, the cam 16 will tend to force the braking shoes 6 and 7 away from each other. If on the other hand an upwardly directed force is exerted upon the bolt 15, a loosening takes place in that the cam 16 pivots over to the right.

This improved brake makes it possible to arrest a load. at any desired and freely suspended position by pulling the driving member 2 by means of the control chain in the lifting sense, whereby the brake shoes are forced apart tosome extent. The braking pressure already existing from the movement of the load is hereby sui'iiciently increased to hold the load freely suspendedat any intermediate position. Lowering is also effected by the control chain which, for this purpose, 'is slightly pulledin the lowering sense thus causing the cam between the braking cheeks to lift. The lowering speed may be regulated bymore or less tightly pulling the chain as this more or less reduces the braking pressure. When lowering the load I normally, the attendant may let the control chain glide lightly through his hand in order to be able at any moment to arrest the load at the desired position by a slight pull'on the chain.

lVhat we claim and desire Letters Patent, is: p

1. A brake for hoists, comprising a drum rotatable in one direction, a pair of blocks within thedrumand arranged to be moved into frictional engagement therewith, a shaft passing through the drum, a cam on the shaft centrally engaging the inner surfaces of the blocks, a driving member, a projection on the latter extending within the drum between the blocksand cooperating with the cam to move said blocks into frictional contact with the inside of the drum.

2. A brake for hoists comprising a drum rotatable in one direction, apair of blocks within the drum having contact atone end with each other and with the inner surface of the drum, a shaft passing through the lat to secure by 'ter, a cam on the shaft having. contact with the blocks, a driving member, and a projection on the latter extending into the drum and into contact with the other ends of the blocks.

3. A brake for hoists, comprising a drum rotatable in one direction, a pair of blocks arranged within the drum and in frictional contact therewith, said blocks having curved end faces and inner curved surfaces between said ends, a shaft passing through the drum, a camon the shaft in contact with said curved. surfaces of the blocks, a driving member, and a projection on the latter extending into the drum and in contact with said end faces. I

4. A brake for hoists, comprising a drum rotatable in one direction, a pair of blocks arrangedwithin the drum in frictional contact therewith and in contact with each other at one end, a shaft passing axially through the drum, a cam on the shaft centrally engaging said blocks, a driving member, a pivoted cam on said member extending within the drum in engagement with the blocks at one end and cooperating with the cam to push the blocks into frictional contact with the inside of the drum.

5. A brake for hoists, comprising a drum rotatable in one direction, a pair of blocks within the drum having contact with each other at one end and with the inner surface of the drum, a shaft passing through the drum, a camon the shaft in contact with the blocks, a driving member alongside the drum, and a pivoted cam on the said member extending into the drum and into contact with the other ends of the blocks.

6. A brake forhoists, comprising a drum rotatablein one direction, a pair of blocks arranged within the drum in frictional contact therewith,-said blocks having curved end faces and inner curved surfaces between In testimony that I claim the foregosaid ends, a shaft passing through the drum, ing as my invention, I have signed my name a cam on the shaft in contact With said in presence of two subscribing Witnesses.

curved surfaces, a driving member, and a HER-MANN GRAUMU'LLER. pivoted cam on the latter extending into the Wit drum and into contact With said curved ends HENRY HAsPER,

0f the blocks. WOLDEMAR HAUPT.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

